A battery in a rechargeable system refers to a package containing several circuit elements, including one or more electrochemical cells, and can often include other circuitry. The package is mechanically adapted to attach to a device that is powered by the battery and to a charger that can recharge the battery while it is attached to the device, or by itself. It is common in some industries to include circuitry in the battery that can provide information to components such as a charger and a device powered by the battery. In some cases the circuitry can include a memory device that stores battery data.
Providing access to a circuit in the battery is a way that it can be accessed by both a charger and a device powered by the battery presents several problems. For one, different components (e.g. charger, device) can apply different voltage levels to the circuit being accessed. As such, if both components attempt to access the circuit, the difference in voltage could interfere with the operation of the circuit or output of the circuit as read by one or both components. In some cases the voltage difference could damage one of the components. In addition, even if all components were able to use identical voltage levels, each component being essentially an initiator and the logic circuit in the battery being a responder, there can be collisions in communication where both components attempt access at the same time.
Accordingly, there is a need for a method and apparatus for controlling access to a logic circuit in a battery by multiple components.
Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of embodiments of the present invention.
The apparatus and method components have been represented where appropriate by conventional symbols in the drawings, showing only those specific details that are pertinent to understanding the embodiments of the present invention so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein.